The vestibular system is the parts of the brain and inner ear that process the sensory information involved with controlling eye movements and balance.1 The receptors located within the inner ear respond to gravity and detect motion and change of head position. They interpret speed and direction of movement, relationship to gravity, and impact balance, posture, and bilateral coordination.2
A properly functioning balance system allows people to see clearly while moving and to determine direction and speed of movement. It also identifies orientation with respect to gravity and directs the body to make automatic postural adjustments to maintain posture and stability in various activities and conditions.3
Balance is achieved by a complex set of sensorimotor control systems that include sensory input from vision (sight), proprioception (touch), and the vestibular system (motion, equilibrium, and spatial orientation).4 The vestibular and visual systems are inseparably linked as neurological and functional connections. Together, visual perception and vestibular coordination provide the foundation for skillful movement through space. Proprioceptors in the neck, eyes, and body help to coordinate movements of the body to orient the head to the task at hand, which enables the body to maintain balance.5
The visual system has sensory receptors in the retina called rods and cones. When light strikes them, they send impulses to the brain that provide visual cues identifying orientation to other objects. The proprioceptive information received from the skin, muscles, and joints involves sensory receptors that are sensitive to pressure or stretch in the surrounding tissues. Cues from the neck indicate the direction the head is turned. Cues from the ankles indicate the body’s movement or sway relative to both the standing surface and the quality of that surface, whether it is hard, soft, slippery, or uneven. The vestibular system, which in each ear includes the utricle, saccule, and three semicircular canals, provides sensory information about motion, equilibrium, and spatial orientation. The utricle and saccule detect gravity and linear movement. The semicircular canals detect rotational movement. All of this information is sorted out and integrated with learned information through the brain stem to the cerebellum and the cerebral cortex to result in establishing balance.6
Disorientation can occur if the sensory input from the eyes, muscles and joints, or vestibular system conflict with one another. This can occur through injury, disease, or the aging process that disrupts the integrated sensorimotor feedback. Impaired balance can be accompanied by dizziness, vertigo, vision problems, nausea, fatigue, and concentration difficulties.7
Balance and vestibular coordination is required for children to enjoy playing on playground equipment. Climbing on ladders, rock walls, and cargo nets all take coordination and balance adjustments to successfully navigate them. Children need vestibular coordination and good visual perception to overcome a fear of heights.8
Children who have difficulty with sensory integration may have difficulty with balance. If they have under-responsive vestibular systems, they may have difficulty standing up straight and lack coordination. If they have over-responsive vestibular systems, they may experience motion sickness and dizziness and dislike being picked up. Therapists have discovered that children can be helped by engaging in rhythmical movement activities, such as sitting in rocking chairs, swings, and hammocks.9
- 1. “Vestibular Exercises for Children.” Livestrong.com. < http://www.livestrong.com/article/215788-vestibular-exercises-for-children/ > 16 Sep. 2010.
- 2. “Visual-Vestibular Coordination.” Occupational Therapy Associates. < www.otawatertown.com/pdfs/vis-vestibular.pdf > 16 Sep. 2010.
- 3. Haven, Lisa. “The Human Balance System – A Complex Coordination of Central and Peripheral Systems.” Vestibular Disorders Association. < http://www.vestibular.org/ > 16 Sep. 2010.
- 4. Ibid.
- 5. Op. cit., “Visual-Vestibular Coordination.”
- 6. Op. cit., Haven, Lisa.
- 7. Ibid.
- 8. Frost, Joe L., Pei-San Brown, John A. Sutterby, Candra D. Thornton, The Developmental Benefits of Playgrounds. Olney, MD: Association for Childhood Education International, 2004. p. 57.
- 9. Ibid., p. 172.